External fixation device

ABSTRACT

An external fixation system for the correction of long bone deformities includes an elongate beam element having an engagement feature along a longitudinal edge of the elongate beam element, a connector element secured to the elongate beam and structurally configured to support a first bone anchor extending from the external fixation system, and a movable carriage engaged with the engagement feature along the longitudinal edge of the elongate beam element and selectively movable along the engagement feature of the elongate beam element. The movable carriage is selectively lockable into a position along the elongate beam element. The movable carriage is structurally configured to support a second bone anchor extending from the external fixation system.

PRIORITY DATA

This application claims priority to and the benefit of the filing dateof Provisional Patent Application No. 61/992,964, filed May 14, 2014,and entitled “Modular Rail Based External Fixation for SkeletalDeformity Correction,” and is a continuation of U.S. patent applicationSer. No. 14/712,471, filed May 14, 2015, and entitled “External FixationDevice, the disclosures of which are both hereby incorporated byreference in their entirety.

FIELD OF THE INVENTION

This application relates to systems that aid in the correction of longbone deformities of the skeletal system including limb lengthening.

BACKGROUND

Many systems exist on the market today to address long bone deformities.They include ring based systems such as the Ilizarov type fixation whichcan be built to suit the particular deformity being addressed, spatialframe type fixators that utilize software and a 6 degree of freedom(6-DOF) capability to address a very broad range of deformities withouta built to suit configuration, and several linear based systems thathave varying degrees of mobility that can be built to suit, withlimitation, the deformity being addressed. Generally, the linear basedsystems are the easiest to apply and to adjust throughout the correctionprocess and they also do not require software. However, unlike thesoftware driven 6-DOF spatial frames, these devices, at times throughoutthe correction process, may have to be reconfigured to address changesthat occur due to the changes to the bone from being partiallycorrected.

All linear systems utilize bone pins or bone anchors otherwise known ashalf pins anchored in groups to each of the bone segments in need ofmanipulation. Individual components, referred to as clamps or anchorblocks, are then attached to each of the bone anchor groups. Thesecomponents act to structurally link the pins within each group togetherand provide an interface to the greater structure at large. One type oflinear structural element, typically referred to as a rail, can then beattached to the clamp interface associated with each bone segmentlinking the segments together completing the overall structure. In mostexisting systems, these rails are available in multiple lengths to suitthe particular condition. In some systems, these rails can be connectedtogether to create a variety of lengths, however, in such systems, theseconnections often become a weak area and at times can be difficult totraverse with a traveling clamp. The clamps themselves are either lockedto the rail or are free to travel along the rail. To affect such motionalong the rail, elongate-able struts are used. Usually these come in theform of threaded rods and nuts whereby the nut is affixed to one clampwhile the rod is affixed to the other. Rotation of the rod within thenut causes the two connected clamps to move relative to one anotheralong the length of the rail. In all such systems the rail providesalignment and resistance to bending and torsional moments but does notprovide any load support along the long axis of the rail, leaving thatfunction to the elongate-able strut.

What is desired is an easy-to-apply linear based system that is modularand easily reconfigurable such that these changes can be made withouthaving an exceedingly complex device configuration. The devices,systems, and methods disclosed herein address one or more of theshortcomings of the conventional system.

SUMMARY

An external fixation system for the correction of long bone deformitiesincludes an elongate beam element having an engagement feature along alongitudinal edge of the elongate beam element, a connector elementsecured to the elongate beam and structurally configured to support afirst bone anchor extending from the external fixation system, and amovable carriage engaged with the engagement feature along thelongitudinal edge of the elongate beam element and selectively movablealong the engagement feature of the elongate beam element. The movablecarriage is selectively lockable into a position along the elongate beamelement. The movable carriage is structurally configured to support asecond bone anchor extending from the external fixation system.

An external fixation system for the correction of long bone deformitiesincludes a movable carriage structurally configured to support a boneanchor extending from the external fixation system. The movable carriageincludes a drive system having a rotatable element engagable with anengagement feature of an elongate beam element in a manner that rotationof the rotatable element advances the movable carriage along theelongate beam element and a selectively actuatable lock system to fixthe movable carriage in a position along the elongate beam element.

An external fixation system for the correction of long bone deformitiesincludes an elongate beam element having an engagement feature along alongitudinal edge of the elongate beam element, a connector elementsecured to the elongate beam and structurally configured to support afirst bone anchor extending from the external fixation system, and amovable carriage engaged with the engagement feature along thelongitudinal edge of the elongate beam element and selectively movablealong the engagement feature of the elongate beam element. The movablecarriage is selectively lockable into a position along the elongate beamelement. The movable carriage is structurally configured to support asecond bone anchor extending from the external fixation system. Thefixation system further includes a supplementary beam element configuredto fixedly attach to an end of the elongate beam element.

An external fixation system for the correction of long bone deformitiesincludes a primary beam element and a secondary beam element. Each ofthe primary and secondary beam elements includes an engagement featurealong a longitudinal edge thereof. The primary and secondary beamelements are securable to each other so that the engagement features ofboth the primary and secondary beam elements form a continuousengagement feature across the primary and secondary beam elements whensecured to each other. The system further includes a carriage elementconnectable to the primary and secondary beam elements and comprising adrive system configured to engage with the continuous engagement featureand move the carriage element along the primary and secondary beamelements. The carriage element is structurally configured to support abone anchor extending from the external fixation system.

Additional embodiments include connections between the rail segments andthe anchor blocks that allow for adjustment of the angle between theanchor blocks and the beam elements. Some embodiments incorporate aturntable on the moving carriage or fixed connector. Other embodimentsinclude a hinge incorporated in the anchor block. Additional embodimentsinclude a hinge element that connects two beam elements to allow theframe to span a joint and allow for joint function. Some embodimentsinclude a hinge element or a family of hinge elements whose mounting canbe adjusted such that a full range of hinge axis locations can beachieved. These hinge elements may benefit by having the same interfaceas the rail connection. With a similar interface added to the anchorblocks themselves, a high degree of flexibility can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate embodiments of the devices andmethods disclosed herein and together with the description, serve toexplain the principles of the present disclosure.

FIG. 1 is a diagram showing an illustrative fixation system attached toa bone according to one example constructed according to principlesdescribed herein.

FIG. 2 is diagram showing an illustrative set of beam elements accordingto one example constructed according to principles described herein.

FIG. 3 is a diagram showing an exploded view of components of a movablecarriage on a beam element configured to engage beam elements accordingto one example constructed according to principles described herein.

FIG. 4 is a diagram showing a cross-sectional view of the movablecarriage on a beam element according to one example of principlesdescribed herein.

FIG. 5 is a diagram showing a different cross-sectional view along lines5-5 in FIG. 4 of the movable carriage according to one exampleconstructed according to principles described herein.

FIG. 6 is a diagram showing an illustrative rotatable element of a drivesystem according to one example constructed according to principlesdescribed herein.

FIGS. 7A, 7B, and 7C are diagrams showing an illustrative lock elementaccording to one example constructed according to principles describedherein.

FIGS. 8A, 8B, and 8C are diagrams showing various views of a movablecarriage with a rotating mechanism according to one example constructedaccording to principles described herein.

FIGS. 9A and 9B are diagrams showing an illustrative slotted hingeelement and an illustrative rotational hinge element according toexamples constructed according to principles described herein.

FIGS. 10A and 10B are diagrams showing an illustrative rotational hingeelement connected to a fixed connector element at an end of a beamelement according to one example constructed according to principlesdescribed herein.

FIGS. 11A and 11B are diagrams showing an illustrative rotational hingeelement connected to an anchor block that is connected to a fixedconnector element at an end of a beam element according to one exampleconstructed according to principles described herein.

FIGS. 12A and 12B are diagrams showing a strut configured to causerotation of an anchor block according to one example constructedaccording to principles described herein.

FIG. 13 is a diagram showing an illustrative beam element with a set ofstraight teeth as an engagement feature according to one exampleconstructed according to principles described herein.

FIG. 14 is a diagram showing an exploded view of a movable carriage witha ratchet mechanism and a beam element according to one exampleconstructed according to principles described herein.

FIG. 15 is a diagram showing a side view of the ratchet mechanismaccording to one example constructed according to principles describedherein.

FIG. 16 is a diagram showing a cross-sectional view of the movablecarriage with the ratchet mechanism and the beam element according toone example constructed according to principles described herein.

FIG. 17 is a diagram showing a perspective view of a fixed connectorelement that connects to an end of the beam element according to oneexample constructed according to principles described herein.

FIGS. 18A and 18B are diagrams showing a hinged anchor block connectedto the fixed connector element according to one example constructedaccording to principles described herein.

DETAILED DESCRIPTION OF THE DRAWINGS

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the embodimentsillustrated in the drawings, and specific language will be used todescribe the same. It will nevertheless be understood that no limitationof the scope of the disclosure is intended. Any alterations and furthermodifications to the described devices, instruments, methods, and anyfurther application of the principles of the present disclosure arefully contemplated as would normally occur to one skilled in the art towhich the disclosure relates. In particular, it is fully contemplatedthat the features, components, and/or steps described with respect toone embodiment may be combined with the features, components, and/orsteps described with respect to other embodiments of the presentdisclosure.

FIG. 1 is a diagram showing an illustrative fixation system 100 attachedto a bone 101. For purposes of discussion, the bone 101 is shown in anintact, un-deformed state. According to the present example, thefixation system 100 includes an elongate beam element 102, a fixedconnector element 108 positioned at an end 109 of the elongate beamelement 102, and a movable carriage 116 secured to the elongate beamelement 102.

The elongate beam element 102 is made of a sturdy material such as metalor a composite material. In the present example, the elongate beamelement 102 has a substantially rectangular cross-section perpendicularto the longitudinal axis of the elongate beam element 102. In someexamples, the elongate beam element 102 is substantially solid. In otherexamples, however, the elongate beam element 102 may have a hollowinterior to allow for a lighter weight beam element. The hollow interiorcan be designed such that the elongate beam element 102 maintainssufficient strength.

The elongate beam element 102 includes an engagement feature 106 along alongitudinal edge 104 of the elongate beam element 102. In the presentexample, the engagement feature 106 includes a concave portion along thelength of the elongate beam element 102. The engagement feature 106 mayinclude a set of engagement elements 107. In some examples, theengagement elements 107 include a straight set of teeth. In someexamples, however, the engagements elements 107 include helical threads.The engagement feature 106 is designed to engage with a drive system ofthe movable carriage 116. The drive system will be described in furtherdetail below.

The movable carriage 116 is designed to securely attach to and movealong a portion of the length of the elongate beam element 102. In thepresent example, the movable carriage 116 includes an opening 111 thatis sized and shaped to allow the elongate beam element 102 to passtherethrough. The movable carriage 116 includes a drive system(described below) that is configured to move the movable carriage 116along the elongate beam element 102 and lock the movable carriage 116into a set position selectively preventing additional movement.

The movable carriage 116 is attached to an anchor block 118. As will bedescribed in further detail below, the anchor block 118 may be connectedto the movable carriage 116 via a turntable, a hinged element, someother adjustable connector, some other inadjustable connector, or morethan one of these. The anchor block 118 is designed to hold an anchorset 122 of bone anchors 114 such as bone pins, bone screws, or bonebolts. The bone anchors 114 are designed to engage with the bone 101.

The fixed connector element 108 is similar to the movable carriage 116except that the fixed connector element 108 does not move along theelongate beam element 102. In one example, the fixed connector element108 is designed to securely and immovably engage with the engagementfeature 106 of the elongate beam element 102. In some examples, asillustrated in FIG. 1, the fixed connector element 108 is secured to theend 109 of the elongate beam element 102.

The fixed connector element 108 is also attached to an anchor block 110.Depending on the embodiment, the anchor block 110 may also be connectedto the fixed connector element 108 via a turntable, hinged element, orboth. The anchor block 110 is designed to hold a different anchor set112 of bone anchors 114.

Because the position of the movable carriage 116 is adjustable, thesecond set 122 of bone anchors 114 is movable with respect to the firstset 112 of bone anchors 114. Thus, while the bone anchors 114 from bothsets 112, 122 are anchored into the bone 101, the movable carriage 116can be adjusted to move the bone anchors 114 and correct various bonedeficiencies and/or perform various bone lengthening operations.

FIG. 2 is diagram showing an illustrative beam set 212 of beam elements102, 202. The set 212 includes the elongate beam element 102 and asupplementary beam element 202. In some cases, the elongate beam element102 may be referred to as the primary beam element and the supplementarybeam element 202 may be referred to as the secondary beam element. Insome cases, during a bone procedure, it may be desirable to extend themovable carriage beyond the length of the original elongate beam element102. According to principles described herein, a supplementary beamelement 202 that matches the elongate beam element 102 is secured to anend 208 of the elongate beam element 102. In other words, thecross-sectional shape of the supplementary beam element 202 that isperpendicular to longitudinal axis 210 is substantially similar to thecorresponding cross-sectional shape of the elongate beam element 102.

The supplementary beam element 202 includes an engagement feature 206along the longitudinal edge 204 of the supplementary beam element 202.The engagement feature 206 matches the engagement feature 106 of theelongate beam element 102. Thus, when the supplementary beam element 202is secured to the elongate beam element 102, there is a singlecontinuous engagement feature 205 that spans both beam elements 102,202.

In one example, the supplementary beam element 202 is connected to theelongate beam element 102 via a set of threaded fasteners 216. In thepresent example, both beam elements 102, 202 include two through-holes218 running the length of the beam elements 102, 202, and spaced away oneither side of a centerline represented by axis 210. At the end of eachof these through-holes 218 is a machined thread 224 that serves toaccept either a threaded bushing 220 or a threaded insert 222. On theside with the threaded insert 222 there is also a counter-bore. Thethreaded bushing 220 on one of the beam elements aligns with and isinserted within the counter-bore of the other. A threaded fastener 216aligned within the through-holes 218 captured between the threadedinsert 222 and threaded bushing 220 is inserted through the threadedbushing 220 and into the threaded inserts 222 within the adjoined beamelement. The head of the threaded fastener 216 bears upon the insideface of the threaded bushing 220. The tensile load in the threadedfastener 216 therefore draws the end faces of the adjoined beam elementstogether under load. The beam elements 102, 202 are primarily subjectedto bending due to the offset loading. The substantially rectangular beamsection is so positioned to maximize the beam element's moment ofinertia by subjecting the width of the beam element rather than thethickness of the beam element to the greatest bending moment. By spacingthe through-holes 218 and thus the threaded fasteners 216 as far awayfrom the centerlines of the beam as practicable, the contribution interms of tensile capability and compressive preload generated ismaximized, giving the connection between the beam elements 102, 202 highstrength and resistance to separation.

FIG. 3 is a diagram showing an exploded view of components of a movablecarriage 116 configured to engage the elongate beam element 102.According to the present example, the movable carriage 116 includes amain body 301 and a drive system 302 that includes a drive shaft 308 anda rotatable element 306. The movable carriage 116 also includes a lockelement 304.

As described above, the movable carriage 116 is designed to move alongthe elongate beam element 102. To accomplish this, the rotatable element306 of the drive system 302 is inserted into a recess 316 on the side ofthe main body 301 of the movable carriage 116 that coincides with theengagement feature 106 on the elongate beam element 102. In the presentexample, the rotatable element 306 is a male helical screw havingengagement features 314 while the engagement elements 107 on the beamelement 102 take the partial form of a female helical thread of the sametype. The rotatable element 306 is held in place with a drive shaft 308that pins the rotatable element 306 within the movable carriage 116. Thedrive shaft 308 extends through holes 318 (only one is shown) onopposing sides of the recess 316 and through a center opening 320 of therotatable element 306. Once assembled, the movable carriage 116 isunable to slide along the elongate beam element 102 because ofmechanical interference between the engagement features 314 and theengagement elements 107. In some embodiments, the lock element 304 mayprevent the rotation of the rotatable element 306. Rotation of therotatable element 306 will cause the movable carriage 116 to be drivenalong the beam element 102. In some examples, when the rotatable element306 is not snapped into place within the recess 316 of the movablecarriage 116, the movable carriage 116 can slide freely along the beamelement 102.

According to the present example, the lock element 304 is inserted intothe same recess 316 as the rotatable element 306 to prevent theunintended rotation of the rotatable element 306. In some examples, thelock element 304 is configured to lock the rotatable element 306 frombeing rotated in either direction. In one example, the lock element 304is configured to allow for rotation in one direction but not bothdirections in manner such as a ratchet. In some examples, the lockelement 304 provides for a manual override such that when an externalforce is applied to the lock element 304, the lock element 304 unlocksthe rotatable element 306. The lock element will be discussed in greaterdetail below.

FIG. 4 is a diagram showing a cross-sectional view of the movablecarriage 116. FIG. 4 illustrates the rotatable element 306 engaged withthe engagement feature 106 of the beam element 102. In some embodiments,the rotatable element 306 engages with the drive shaft 308 such thatrotation of the drive shaft 308 causes corresponding rotation of therotatable element 306. For example, in some embodiments, the drive shaft308 has a non-circular cross-section that engages a non-circular centralopening 320 in cross-section of the rotatable element 306. Accordingly,the drive shaft 308 and the rotatable element 306 rotate together. Insome examples, the cross-sections are D-shaped. In other examples, theyhave other interfering or non-circular shapes. In some cases, loadingthat is applied to the movable carriage 116 is transferred into thedrive system 302 engaged with the beam element 102.

FIG. 5 is a diagram showing a different cross-sectional view of themovable carriage 116, particularly, through line 5-5 of the device shownin FIG. 4. FIG. 5 shows a polygonal portion 502 of the rotatable element306. The polygonal portion 502 is designed to fit with a lock element304 as will be described in further detail below. The view alsoillustrates the non-circular drive shaft 308 positioned within thecenter opening 320 of the rotatable element 306. FIG. 5 also shows theholes 504 that can be used to secure the anchor block 118 to the mainbody 301 of the movable carriage 116. Such holes 504 can be positionedon both sides of the body. In the present view, the holes are not seenon the top because the anchor block 118 is shown secured to the mainbody 301. The holes 504 may be formed in bosses that project from thesurface of the body. The anchor block 118 may include receiving boresthat receive the bosses enabling easy and simple alignment of the anchorblock 118 and the carriage. In some embodiments, such as the one shown,the bosses are frusto-conically shaped to enable simple matchup ofcomponents.

As illustrated in the cross-sectional view, the anchor block 118includes a passage 506 through which bone anchors (e.g. 114, FIG. 1) maybe placed. The bone anchors 114 can then be locked in place through useof a set screw (not shown) that is placed into passage 508.

FIG. 6 is a diagram showing an illustrative rotatable element 306 of thedrive system 302. According to the present example, the rotatableelement 306 includes an engagement feature 314 that includes engagementelements 604 designed to engage an engagement feature (e.g. 106, FIG. 1)of a beam element (e.g. 102, FIG. 1). In this example, the engagementelements 604 are male helical threads.

The rotatable element 306 also includes a non-circular locking portion,shown as a polygonal portion 502 such as a hex portion. The polygonalportion 502 has flat edges that when engaged with tabs of a lock element(e.g. 304, FIG. 3), prevent rotation of the rotatable element 306. Onboth sides of the polygonal portion 502 are circular portions 608. Whenthe tabs of the lock element (e.g. 304, FIG. 3) are placed over thecircular portions 608, rotation of the rotatable element 306 is allowed.

FIGS. 7A, 7B, and 7C are diagrams showing an illustrative lock element304. FIG. 7A is a top view of the lock element 304, FIG. 7B is across-sectional view of the lock element 304 along line 7B-7B, and FIG.7C is a perspective view of the lock element 304. According to theexample shown, the lock element 304 includes a body 701 that houses twospring-loaded key elements 702 that are biased away from each other witha bias element 708. The key elements 702 include tabs 704 that extendoutwardly on opposing sides of the body 701. When the lock element 304is inserted into the recess 316 of the movable carriage (e.g. 116, FIG.1), the key elements 702 are pressed toward each other such that thetabs 704 of the key elements 702 can fit into the recess 316. The keyelements 702 are aligned to fit within the slots 322 in the recess shownin FIG. 3. After passing into the recess 316, the key elements 702 arereleased and the bias element 708 forces the key elements 702 away fromeach other such that the tabs 704 extend into undercut slots (e.g., 322,FIG. 3) to prevent the lock element 304 from being removed from themovable carriage 116. The lock element 304 includes tabs 706 that areshaped and formed to extend into the recess 316 in a directiontransverse to the axis 210 of the elongate beam element 102. These tabs706 are arranged to prevent rotation of the lock element 304 whendesired. With the lock element 304 placed into the recess 316, the tabs706 extending from the body 701 fit over the polygonal portion 502 ofthe rotatable element 306 so as to prevent rotation thereof.

FIG. 7B shows the tabs 706 and the bias element 708 that biases the keyelements 702 away from each other. In the embodiments shown, the tabs706 have parallel inner surfaces 714 that engage the polygonal portion502. In addition, the tabs 706 are connected by a portion of the body701 having engagement surfaces 712 that may also engage the polygonalportion 502 of the rotatable element 306. This can be seen in thecross-section of FIG. 5. Other arrangements for preventing relativerotation between the rotatable element 306 and the lock element 304 arealso contemplated.

To disengage the lock element 304, the body 701 is slid in a directionalong the longitudinal axis 610 of the rotatable element 306. A recessedportion 710 within the body 701 allows for easier gripping of the bodyto move the lock element 304 accordingly. Moving the lock element 304 assuch moves the tabs 706 out of engagement with the polygonal portion 502and into engagement with the circular portion 608, thereby allowingrotation of the rotatable element 306. In addition to the abovedescribed example of the lock element 304, other locking mechanisms forsecuring the rotatable mechanism are contemplated. For example, as willbe described in further detail below, the rotatable element 306 and thelock element 304 may form a ratchet mechanism.

FIGS. 8A, 8B, and 8C are diagrams showing various views of a movablecarriage 116 with a rotating mechanism 802. Here, for clarity, themovable carriage 116 is shown without the lock element 304. FIG. 8Aillustrates a top view of the rotating mechanism 802, FIG. 8Billustrates a cross-section along line 8B-8B and FIG. 8C illustrates across-section along line 8C-8C. The rotating mechanism 802 is arrangedto connect to the anchor block 118 (FIG. 1) and permit the anchor block118 to rotate relative to the movable carriage 116 and in relation tothe elongate beam element 102. In so doing, the bone anchors 114 carriedby the anchor block 118 may be rotated and angled to a desired positionto facilitate treatment of the patient. In the example shown, themovable carriage 116 includes two rotating mechanisms 802, one on eachof two opposing sides. Typically, the anchor block 118 is attached toonly one side. However, some treatment regimes may include anchor blockson both sides.

According to the present example, the rotating mechanism 802 includes acylindrical turntable 803 fit within a corresponding recess 805 that ismachined into a side of the movable carriage 116. Here, the recess isformed so that a boss 807 projects in a central region of the recesswith the turntable 803 rotatable about the boss 807. The cylindricalturntable 803 may be secured to the movable carriage 116 with a snapring 809.

The turntable 803 includes a first set 810 of gear teeth 806 that aredesigned to match and engage with a corresponding set of engagementfeatures 808 on a radially driven key 804. When the engagement features808 of the key 804 are engaged with the gear teeth 806, they preventrotation of the turntable 803. The key 804 fits within a pocket 816 inthe movable carriage 116. The pocket 816 intersects with the cylindricalrecess 805 that holds the turntable 803. The key 804 is driven into andout of engagement with the turntable 803 through the action of acaptured set screw 818.

In the present example, there are two sets 810, 812 of gear teeth 806.The first set 810 of gear teeth 806 spans a larger arc and allows forrotation to be set across a range of angles. The second set 812 of gearteeth 806 is smaller and allows for ease of setting the turntable 803into a given rotation position as indicated above. The turntable 803 canbe positioned on one side of the movable carriage or both sides of themovable carriage 116. In some examples, however, the turntable 803 maynot be present on the movable carriage 116. The turntable 803 includes aset of holes 822 that allow for connection to an anchor block (e.g. 118,FIG. 1). In some aspects, the holes 822 are threaded and receive boltsextending from or through the anchor block 118. As can be seen in FIG.8A, the holes 822 are spaced farther in a longitudinal direction than inthe lateral direction. Here, the holes 822 are formed as bosses thatproject from the surface of the turntable. The anchor block 118 mayinclude receiving bores that receive the bosses enabling easy and simplealignment of the anchor block 118 and the carriage. With the anchorblock 118 secured to the turntable 803, the bone anchors 114 extendingfrom the anchor block can be angulated with respect to the beam element102.

FIGS. 9A and 9B are diagrams showing an illustrative slotted hingeelement 900 and an illustrative rotational hinge element 920. FIG. 9Aillustrates the slotted hinge element 900. The slotted hinge element 900includes a hinge bracket 904 and a hinge yoke 902. The hinge bracket 904includes a pair of slots 908 that allow the hinge bracket 904 to beconnected to the end of a beam element (e.g., 102, 202), a connectorelement (e.g. 108), or an anchor block (e.g. 110). Thus, the slots 908can be sized and spaced to allow for such a connection. The hingebracket 904 rotates about an axis 906 formed by a hinge or pivotconnection with respect to the hinge yoke 902. The axis 906 is definedby hinge pins 909. In some embodiments, the hinge pins 909 are hollowand can receive a guide pin therethrough. The hinge yoke 902 may beshaped and arranged to connect to a different beam element (e.g. 102,202) which may be a curved beam element. In some examples, the hingeyoke 902 includes two connection holes (not shown) that may be sized andshaped to align with the through-holes 218 of the elongate beam element102. The slots 908 allow for placement of the slotted hinge element 900anywhere along their length or within their envelope. The slots 908 maybe straight in form (as illustrated) to allow for simple translation, orcurved to allow for rotation about an arbitrary point in space or acombination of straights and curves to allow for a continuum ofrotational centers. Because the slotted hinge element 900 can beconnected to either a beam element (e.g. 102, 202), the movable carriage(e.g. 106, FIG. 1), the connector element (e.g. 108, FIG. 1), or ananchor block (e.g. 110, 118), a chain of such slotted hinge elements 900having multiple degrees of freedom can be achieved.

FIG. 9B illustrates the rotational hinge element 920. The rotationalhinge element 920 includes a hinge bracket 912 with a rotating connectorelement 914. The rotating connector element 914 is configured to connectto a beam element (e.g., 102, 202), a connector element (e.g. 108), oran anchor block (e.g. 110) while allowing the hinge bracket 912 torotate with respect to the component to which it is attached. The hingebracket 912 is also connected to a hinge yoke 902. In this embodiment,the rotating connector element 914 is formed of a series of radiallyextending splines configured to interdigitate with corresponding splineson the opposing component. The rotating connector element 914 may have aknurled surface, a roughened surface, or other friction inducingfeatures that allow the hinge yoke 902 to securely connect in a desiredorientation.

FIGS. 10A and 10B are diagrams showing an illustrative rotational hingeelement 920 connected to a connector element 108 at an end of a beamelement 102. FIG. 10A illustrates a top view and FIG. 10B illustrates aside view. In this example, the rotational hinge element 920 isconnected to the connector element 108. Additionally, a temporary guidepin 1002 is placed along the axis 906 through the hinges. In oneexample, the temporary guide pin 1002 can temporarily be inserted at theaxis of rotation of a patient's knee. This allows the axis 906 of therotational hinge element 920 to be aligned with the axis of rotation ofthe knee. For example, in the case where the fixation system 100 is tobe used to perform operations on the femur, the hinge yoke 902 can beconnected to a device that is attached to the part of the leg distal tothe knee, with the axis 906 appropriately aligned with the axis of theknee.

FIGS. 11A and 11B are diagrams showing an illustrative rotational hingeelement 920 connected to an anchor block 110 that is connected to aconnector element 108 at an end of the elongate beam element 102. FIG.11A illustrates a top view and FIG. 11B illustrates a side view. In thisexample, the anchor block 110 is connected to the connector element 108through a rotating mechanism 802 such as a turntable (e.g. 803, FIG. 8).Thus, the rotational hinge element 920 moves with the anchor block 110as the anchor block 110 rotates with respect to the connector element108.

FIGS. 12A and 12B are diagrams showing a strut assembly 1202 configuredto cause rotation of anchor block 118. Thus, the strut assembly 1202 isused as a means of angulation for the set of bone anchors 114. In thepresent example, the beam element 102 is shown with a fixed connectorelement 108 attached to one end 1206. The connector element 108 may haveeither a fixed anchor block interface or a turntable (e.g. 803, FIG. 8A)in the locked state. At the other end 1204 of the beam element 102, amovable carriage 116 is positioned along and fixed to the beam element102 at a particular location. The movable carriage 116 has a rotatingturntable 803 to connect to the anchor block 118. The strut assembly1202 is attached to one common interface of each of the two anchorblocks 110, 118. The line of action of the strut assembly 1202 is offsetfrom the axis of rotation of the turntable 803. In this configurationthe strut-to-block connection includes a revolute joint, the axis ofwhich is parallel to the axes of the turntable 803, resulting in atriangular linkage arrangement. One link is the beam element 102, thesecond is the length of the strut assembly 1202 and the third is theoffset distance between the axis of rotation of the turntable 803 andthe axis of the attached strut revolute joint. The change in the lengthof any side of a triangle while the other two sides remain fixed inlength will result in the change in all of the angles of the triangle.The result is that the anchor block 118 is forced to rotate relative tothe beam element 102. Other means of achieving the same are alsocontemplated.

FIG. 13 is a diagram showing a fixation system 1300 with an illustrativeelongate beam element 102 in a different configuration with a set ofstraight teeth 1304 as an engagement feature 1301. The fixation system1300 includes a fixed connector element 108 and a movable carriage 116that is driven along the beam element 102 through use of a rotatablegear 1302 that engages with the straight teeth 1304. Accordingly, therotation system operations as a rack and pinion system. In the presentexample, the fixed connector element 108 is fixed to the beam element102 with a locking plate 1308 that is configured to clamp to the beamelement 102 when the screws 1310 are tightened. The movable carriage 116holds the rotatable gear 1302 in a driver plate 1312, which in thisembodiment is connected to or forms part of the movable carriage 116with screws 1314 and partially wraps around the beam element 102. Inthis example, a hex key can turn the rotatable gear 1302 by insertingthe hex key into the key-hole 1306 positioned at the center of the axisof rotation of the rotatable gear 1302. In some examples, the driverplate 1312 incorporates a ratchet mechanism or a locking element thatwould prevent the rotatable gear 1302 from turning in either one or bothdirections to control when and how the movable carriage 116 is movedalong the beam element 102. While the present example illustrates asingle rotatable gear 1302, other examples may have multiple gears.Anchor holes 1318 are arranged to receive bone anchors (e.g. 114, FIG.1). It is noted that a rack and pinion system or straight teeth can beused on all embodiments disclosed herein.

FIGS. 14-16 show an alternative movable carriage 116 with the elongatebeam element 102. FIG. 14 is a diagram showing an exploded view of amovable carriage 116 with a main body 1401 and a drive system 1403 witha ratchet mechanism 1402 used to drive the movable carriage 116 alongthe beam element 102. In the present example, the ratchet mechanism 1402includes a body 1406, a direction indicator 1404, and a rotatableelement 1408 having a gear 1410 thereon. To assemble the ratchetmechanism 1402 to the movable carriage 116, the ratchet mechanism 1402is inserted into a recess 1416 in the movable carriage 116. The driveshaft 308 is then inserted into a hole 1412 in the rotatable element1408 of the ratchet mechanism 1402. Snap-rings may be used to secure thedrive shaft 308 in place within the hole main body 1401. The elongatebeam element 102 fits within a passage 1414 in the main body 1401.

The direction indicator 1404 in this embodiment is shown with adirection indicating shape that conveys information to a user aboutwhich direction the movable carriage 116 might move along the elongatebeam element 102. In this embodiment, the shape is shown as an arrowshape. Other shapes, however, are also contemplated.

FIG. 15 is a diagram showing a side view of the ratchet mechanism 1402.The rotatable element 1408 includes engaging portions 1504 and a gear1410. The engaging portions 1504 include helical threads designed toengage with corresponding threads of the engagement feature 106 on thebeam element 102. The gear 1410 includes a number of tooth features 1506that engage a ratchet element attached to the direction indicator 1404as will be described in further detail below.

FIG. 16 is a diagram showing a cross-sectional view of the ratchetmechanism 1402. Here, the beam element 102 is within the passage 1414 ofthe movable carriage 116. The direction indicator 1404 is secured to aratchet element 1602 via a screw 1606. The ratchet element 1602 isbiased against the gear 1410 by a biasing element 1604. The biasingelement 1604 may be a spring such as a helical wire form spring, amonolithic mechanical spring, or an elastomer. As can be seen, the gear1410 includes tooth features 1506 spaced apart with sides forming planesthat are parallel on adjacent tooth features 1506. By changing theposition of the direction indicator 1404, the ratchet element 1602allows or prevents rotation of the gear 1410 and thus the rotatableelement 1408. Specifically, one side of the ratchet element has a stopsurface 1610 shaped to resist sliding when a tooth feature 1506 ispressed against it, while the other side of the ratchet element 1602 hasa sloped surface 1608 such that the act of turning the drive shaft 308presses the ratchet element 1602 away from the rotatable element 1408,thus compressing the biasing element 1604. The tooth feature 1506 thenslides across the ratchet element 1602 until it crosses the entirefeature. The ratchet element 1602 then snaps into the space between thetooth features 1506, thus clicking into a new resting spot.

In the illustrated configuration, the sloped surface 1608 of the ratchetelement 1602 allows for clockwise rotation (from the present view) ofthe gear 1410. But, the stop surface 1610 on the other side of theratchet element 1602 will prevent rotation in the counter-clockwisedirection. If the ratchet element is turned 180 degrees, which can bedone by rotating the direction indicator 1404, the sloped surface 1608will face the opposite way. Thus, counter-clockwise rotation of the gear1410 is allowed while clockwise rotation of the gear 1410 is prevented.In some examples, the ratchet element 1602 is designed such that a 90degree rotation from the present configuration will prevent rotation ofthe gear 1410 in both directions.

The cross-section of the drive shaft 308 is shown with a key 1612 andkeyway used to rotate the drive shaft 308 and thus the rotatable element1408. In this example, the gear 1410 includes six tooth features 1506.In other examples, however, another number of tooth features 1506 may beused. The amount of tooth features 1506 can be selected based on thepitch of the rotatable element helix and the travel distance desired foreach click of the ratchet element 1602.

The ratchet mechanism 1402 allows the drive shaft 308 to rotate therotatable element 1408 in a single direction. The tooth features 1506can be designed symmetrically so that the direction that the rotatableelement 1408 can be set either way based on the orientation of theratchet element 1602. Without such a switchable ratchet element 1602,the direction that the movable carriage 116 could move could be changedby removing the entire ratchet mechanism 1402, flipping its direction,and reinserting the ratchet element 1602.

In some examples, two movable carriages may be connected to the beamelement 102. One of the carriages can be locked permanently to the beamelement 102 by inserting a lock element into the otherwise movablecarriage. The other carriage element can be slide-able, lockable ordrivable, and so the permanently locked carriage can be created byassembling a lock mechanism into the carriage.

FIG. 17 is a diagram showing a perspective view of a connector element108 that connects to an end 109 of the beam element 102. According tothe present example, instead of a connector element 108 that slidesalong the elongate beam element 102 and is locked into place, theconnector element 108 is configured as an end cap. Thus, the connectorelement 108 connects to the beam element 102 in a manner similar to themanner in which the supplementary beam element (e.g. 202, FIG. 2)connects to the beam element 102. Accordingly, that connection will notbe re-described here.

FIGS. 18A and 18B are diagrams showing a hinged anchor block 1810 toconnect to the connector element 108. The hinged anchor block 1810 maybe similar to the hinge elements described above. FIG. 18A illustrates atop view and FIG. 18B illustrates a side view. According to the presentexample, the hinged anchor block 1810 includes a first piece 1806secured to the connector element 108. In some examples, the first piece1806 can be connected to a turntable (e.g. 803, FIG. 8). The first piece1806 is connected to a second piece 1804 via a hinge 1808. Thus, thesecond piece 1804 is rotatable with respect to the first piece 1806about the hinge 1808. The second piece 1804 holds a set of bone anchors114. As illustrated in FIG. 18B, the bone anchors 114 may be pivotedabout an axis defined by the hinge 1808 with respect to the beam element102, thus allowing an additional degree of freedom. As can be seen, theconnector element 108 is configured with holes 822 that are arranged toconnect to the first piece 1806 of the hinged anchor block 1810 in thesame manner as it connects to the anchor block (e.g. 110, FIG. 1).Instead of the holes 822, other connection mechanisms are contemplated.

Persons of ordinary skill in the art will appreciate that theembodiments encompassed by the present disclosure are not limited to theparticular exemplary embodiments described above. In that regard,although illustrative embodiments have been shown and described, a widerange of modification, change, and substitution is contemplated in theforegoing disclosure. It is understood that such variations may be madeto the foregoing without departing from the scope of the presentdisclosure. Accordingly, it is appropriate that the appended claims beconstrued broadly and in a manner consistent with the presentdisclosure.

1. An external fixation system usable in the correction of long bonedeformities, the system comprising; an elongate beam element having anengagement feature along a longitudinal edge of the elongate beamelement; a connector element secured to the elongate beam and comprisinga rotating mechanism adapted to support a first bone anchor andconfigured to selectively adjust the first bone anchor to differentangles in relation to the elongate beam element, the connector elementhaving a recess and the rotating mechanism being disposed in the recess;and a movable carriage engaged with the engagement feature along thelongitudinal edge of the elongate beam element and selectively movablealong the engagement feature of the elongate beam element, the movablecarriage being selectively lockable into a position along the elongatebeam element, the movable carriage being structurally configured tosupport a second bone anchor extending from the external fixationsystem.
 2. The system of claim 1, wherein the rotating mechanism rotatesis centrally disposed on the connector element.
 3. The system of claim1, wherein the rotating mechanism comprises a series of engagementelements, the engagement elements being configured to selectively engagestop elements that prevent rotation of the rotating mechanism.
 4. Thesystem of claim 1, wherein the rotating mechanism comprises a turntable.5. The system of claim 4, wherein the rotating mechanism furthercomprises a key configured to prevent rotation of the turntable when ina first position and to allow rotation of the turntable in a secondposition.
 6. The system of claim 5, wherein the key is configured toprevent rotation of the turntable through inter-digitation of engagementelements of the key with engagement elements of the turntable.
 7. Thesystem of claim 5, wherein the key is configured to engage and disengageengagement elements disposed near an outer diameter of the turntable. 8.The system of claim 7, wherein the key is driven toward and away fromthe engagement elements of the turntable via a rotatable threadedelement.
 9. The system of claim 7, wherein the recess comprises a bosstherein, the rotating mechanism being rotatable about the boss.
 10. Anexternal fixation system usable in the correction of long bonedeformities, the system comprising; an elongate beam element having anengagement feature along a longitudinal edge of the elongate beamelement; a connector element secured to the elongate beam andstructurally configured to support a first bone anchor extending fromthe external fixation system; and a movable carriage engaged with theengagement feature along the longitudinal edge of the elongate beamelement and selectively movable along the engagement feature of theelongate beam element, the movable carriage being selectively lockableinto a position along the elongate beam element, the movable carriagecomprising a rotating mechanism adapted to support a second bone anchorand configured to selectively adjust the second bone anchor to differentangles in relation to the elongate beam element, the movable carriagehaving a recess and the rotating mechanism being disposed in the recess.11. The system of claim 10, wherein the rotating mechanism rotates iscentrally disposed on the connector element.
 12. The system of claim 10,wherein the rotating mechanism comprises a series of engagementelements, the engagement elements being configured to selectively engagestop elements that prevent rotation of the rotating mechanism.
 13. Thesystem of claim 10, wherein the rotating mechanism comprises aturntable.
 14. The system of claim 13, wherein the rotating mechanismfurther comprises a key configured to prevent rotation of the turntablewhen in a first position and to allow rotation of the turntable in asecond position.
 15. The system of claim 14, wherein the key isconfigured to prevent rotation of the turntable through inter-digitationof engagement elements of the key with engagement elements of theturntable.
 16. The system of claim 14, wherein the key is configured toengage and disengage engagement elements disposed near an outer diameterof the turntable.
 17. The system of claim 16, wherein the recesscomprises a boss therein, the rotating mechanism being rotatable aboutthe boss.
 18. An external fixation system usable in the correction oflong bone deformities, the system comprising; an elongate beam elementhaving an engagement feature along a longitudinal edge of the elongatebeam element; a connector element secured to the elongate beam andcomprising a rotating mechanism centrally disposed on the connectorelement and adapted to support a first bone anchor and configured toselectively adjust the first bone anchor to different angles in relationto the elongate beam element; and a movable carriage engaged with theengagement feature along the longitudinal edge of the elongate beamelement and selectively movable along the engagement feature of theelongate beam element, the movable carriage being selectively lockableinto a position along the elongate beam element, the movable carriagebeing structurally configured to support a second bone anchor extendingfrom the external fixation system.
 19. The system of claim 18, whereinthe rotating mechanism comprises a turntable.
 20. The system of claim19, wherein the rotating mechanism further comprises a key configured toprevent rotation of the turntable when in a first position and to allowrotation of the turntable in a second position.